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JUMP

Japan Uncertainty Modelling Project

Climate response to volcanic forcing: Validation of climate sensitivity of a coupled atmosphere-ocean general circulation model

Tokuta Yokohata , Seita Emori , Toru Nozawa , Yoko Tsushima , Tomoo Ogura , Masahide Kimoto

Two versions of a coupled atmosphere-ocean general circulation model (GCM) with different climate sensitivities are tested on global cooling following the Pinatubo volcanic eruption to investigate the validity of high climate sensitivities. The higher-sensitivity version, with climate sensitivity of 6.3 K for doubled CO2 forcing, overestimates cooling due to the volcanic eruption, whereas the lower-sensitivity version (4.0 K) produces results consistent with observations. A simple scheme for climate feedback analysis is devised and it is found that the difference between the two versions is attributed to cloud-albedo feedback. This validation method is expected to provide additional constraints on climate sensitivity and possibly lead to reduced uncertainties in climate prediction.

Geophys. Res. Lett., 32, (L21710)

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